2004 turn signals aren't working

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  • yt1300
    I just registered
    • Oct 2017
    • 6

    2004 turn signals aren't working

    The short version is that my turn signals do not work at all (none of them), nor do my hazard lights. Additionally, when I tried to figure out which wire was the ground and which was positive for the turn signal, they both appear to be ground. To check this, I set the multimeter to measure volts, turned the turn signal on, put the positive probe on the positive end of the battery and tested both terminals inside the light socket with the negative end, and for both terminals, it completed a circuit and showed me 12+ volts. I don’t have a lot of experience with volt meters, so maybe I’m doing something wrong, but if one of those wires was receiving current (as it should have been since the turn signal was on), it wouldn’t have completed a circuit, would it?

    Here is the longer backstory (note: I posted part of this previously, but no one has responded and it has been several days, and the situation has changed some since then).

    I just bought a 2004 grand Cherokee (my first jeep) that I'm trying to fix up and get through road-worthy.

    When I first got it, the passenger's side headlights and turn signals worked fine, but the driver's side were screwed up. The normal beams worked, but when I turned on high beams, the turn signal bulb illuminated and was crazy bright (the high beam bulb did nothing). However, if I activated the right (drivers) turn signal, the high beam bulb flashed dimly.

    I thought this was a side effect of the previous owner installing, then removing some aftermarket driving lights. After a week of trying to find the problem, I gave up and decided to temporarily splice into the wire for the turn signal on the side of the car (just by the door) and run that wire through the drives turn signal (the plan was to do this just to get it through road-worthy, then keep looking for the actual problem). So I ran that wire (from the side turn signal to the main turn signal, then back to the other half of the wire on the side turn signal), and when I tested it, the turn signal flashed rapidly twice, then they all went all over the entire car and haven’t worked since. I have since put the wiring back to its original configuration, but still the turn signals don’t work.

    However, for some magical reason that I don’t understand, my high beams are working correctly now.

    I have no idea what is going on or how to fix it. I can’t find any fuses that look bad, but it seems like it has to be a fuse or a relay somewhere.

    I checked the notorious turn signal relay under the dash, and the casing was blue and looked new, so I suspect it was recently replaced. I opened it up, and the terminals all looked like they were in really good shape. Also, my understanding was that that relay doesn’t affect the hazards.

    If anyone has any clue how to fix this, I would really appreciate it. Thanks.
  • Hoobz
    Full Flexer
    • Feb 2013
    • 1163

    #2
    I've got nothing.

    But I'd be trying to get a hold of a very good wiring diagram for your model and tracing all the associated wires until you find the fault, or no fault.

    The turns signals might be getting processed by one of the computer modules, in this model. Not sure it's 100% just a mechanical relay on it's own type thing.

    Hopefully someone with more knowledge on this pipes up, because auto electrical problems can really hurt, more than mechanical issues
    Either write something worth reading or do something worth writing.

    Comment

    • yt1300
      I just registered
      • Oct 2017
      • 6

      #3
      Update: I found some burnt fuses that either I missed before or blew since I checked last. After replacing them, everything is working...for now. I suspect that there must be some underlying problem that caused the fuses to blow, so if anyone has any suggestions, I'd appreciate it.

      Comment

      • JeanLuke
        Lowranger Shocker
        • Jul 2017
        • 1565

        #4
        Originally posted by yt1300 View Post
        Update: I found some burnt fuses that either I missed before or blew since I checked last. After replacing them, everything is working...for now. I suspect that there must be some underlying problem that caused the fuses to blow, so if anyone has any suggestions, I'd appreciate it.
        Glad you found it. Regarding fuses on bulbs, a blown fuse is not always caused by an underlying problem. A filament bulb has a large current spike when it first turns on (more than ten times normal running current) for that quarter-second or so until the tungsten gets white hot. This can occasionally take out a fuse. The other thing that can do it is if a bulb itself is on the way out. A broken filament can re-connect at half the length, which will give a massive current spike on cold start, yet the bulb will appear to be working.

        My advice is to carry spare fuses, and worry about finding an underlying problem if it happens again.

        Comment

        • yt1300
          I just registered
          • Oct 2017
          • 6

          #5
          Crap, the problem is back to what is was when I first got it (high beam power goes to turn signal bulb, and the turn signal works when the lights are off, but makes the lights flash when they are on; this only happens on the drivers side). Of course, it started doing this again while it was being inspected (needless to say, it failed the safety inspection).

          I've double checked the fuses, and they are all still fine (including the ones that I just replaced).

          I have no clue what is going on, so any advice (or useful wiring diagrams) would be greatly appreciated.

          Comment

          • Classic Boy
            Full Flexer
            • Jun 2017
            • 814

            #6
            Do a search on this forum as there is a link to a full electronic copy of the WG/Wj repair manual. I know because I have previously downloaded it but I don't recall which thread it was in.

            Comment

            • Hoobz
              Full Flexer
              • Feb 2013
              • 1163

              #7
              Originally posted by Classic Boy View Post
              Do a search on this forum as there is a link to a full electronic copy of the WG/Wj repair manual. I know because I have previously downloaded it but I don't recall which thread it was in.
              Was it this one?

              Hi all, does anyone know of any sites where you can download for free the complete workshop service manual for repairing a 2003 WJ CRD jeep grand cherokee? there are many links on the net but none that end up for a 2003 or that are complete. the closest i have is for the 2002 WG at: http://www.colorado4wheel


              From this thread?

              Hi all, does anyone know of any sites where you can download for free the complete workshop service manual for repairing a 2003 WJ CRD jeep grand cherokee? there are many links on the net but none that end up for a 2003 or that are complete. the closest i have is for the 2002 WG at: http://www.colorado4wheel
              Either write something worth reading or do something worth writing.

              Comment

              • ajftj
                AJOR Gold
                • Jun 2017
                • 134

                #8
                Electrical problems can definately drive you mad, cant attempt to fix unless you have the diagram and know how to read it - well when they are random like this. As you dont sound too experienced I'd reccomend you stick to the basic physical checks first. I commend you for the detailed write-up and for having a go.

                Maybe a few general pointers.

                Physically examine the ground point for each lamp where it connects to the body. If you can work out which one it is of course. Typically if you follow the harness back from the lamp connector you would expect to find a break out wire from the bundle that goes to the body. Feel the wire in the harness, maybe there is a splice inside the bundle that is bad. Try switching things on so you have the problem and pulling the harness about to see if you can make it come and go.

                Wierd cross over lighting behaviour is often caused by bad ground.

                Alternatively if you are feeling more adventurous, I don't know if your model has electronic control of the lighting, a body control module or a smart fuse box. Again the wiring diagram is what you need. If you can find the control module, physically inspect any multi plugs, unplug them and have a good look inside for corrosion.

                Another cause of malfunction can be where the module or is connectors get water damage and then voltage can be presented where it should not be, although your problem sounds more a module output / distribution or grounding issue. So also try to identify the module ground(s) and visually check.

                Sorry I can't be more specific to your model, but keep it simple and look for physical issues before you start swapping things around.

                good luck!
                2004 TJ, 4.0L, Manual, finally reliable and fun.

                Comment

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